Stylish will not install styles at all - Chrome

Ive recently tried to install a slack style into stylish, It would not allow it to be installed - at all.I currently use it for a github dark mode, And it worked. When i was not able to install the slack style I reinstalled stylish, and now my github style is gone, and it still will not install styles. Im not absolutely sure how the stylish extension works, so any tips would be lovely.